Lapping machine



J. W. SMITH LAPPING MACHINE Jgne 9, 1925.

Original Filed Dec. 4, 1920 2 Sheets-Sheet l @N NIQN w Lw om .wrm S E.Tl Q N -Hmm June 9, `1925. A

J. W. SMITH "-LAPPLNG MACHINE Y original Filed Dec. 4. 1920 -2sheets-sheet 2 A vwemtoz Patented June 9,5 1925.

eeil'lwiElN-TzoFs-ice-g Jenn` W. Smm; or nnwrnrranv, CONNECTICUT,Assienonrro THE-ranura nnen,

:NG commma- QF NEW Bamm; Sommers@ wareserxolier @Madri- CUT.

. LAPHNG Application-filed. December 4,13` 20, 1Slera1 Ne.:4&,v2p2,2.pRenewed Novemberii, `1924,

To all 'Lu/wm t may concern;-

Be itfknoivn that I, JOHN lV. SMITH, a citiaen of the United States ofAmerica, residing at New BrtainfHaI'tffOrd County, Connecticut, haveinvented a new and useful Lappin g Machine,V of fvvhich, the' followingis a specification. i y

Wy invention` relates to. i machine for grinding or lapping,"` and isparticularly `adapted for grinding or lapping parallel surfaces on'articles, but .isf ,not limited to use onk articles` requiring parallelsurfaces.

It `is an object of Iny invention to provide ainachine for lapping orgrinding Asurfaces 5i which will perform its function andproducealinished product` of a high Ldegree, of accuracy and uniformity.l lngeneral, the vobject is to iinproveand simplify theconstruction ofgrinding or lapping machines.

Other. objects and advantages WillV appear as the specificationproceeds.

In the preferred forin of my, linvention there .isk provided apair oflapping discs mounted upon any suitable typeof frame.

A Work carrier is -interpos ed between the discs. The carrier isprovided witlirneans i-orfholding a plurality of articles to be lapped.rA ineans is provided Lwimparjt to the .carrier a ,unique inovelnentrelatively ,to said discs whereby the articles in the carrier will be`lapped dow-n to uniform dimensions.

1n the-drawings, which show a preferred form of machine. for-the purposeofillustrw tion only- Figure l `is a central vertical sectionaly vienYof a machineembodying rfemtinesof` my invention; and

Fig. yE2 is a 4section taken.substantially in` the plane of thelineuQj-Q of Fig. l.

In said I,diaivingn `5 represents any suitable design of frame forsi-ipportingfthe.partsof niy machine. The upperl par-t,Gviofltliefrainesupports one of the lappin` discs 7; Mounted opppsite i spaced therefromis acoinp-lenientary grind,-

ing or lapping dise 8.k For the purposeof separating" these discs fliaveshown nieanS..

S, for raising-,the latter and.separatinggthe The discs 7 all@ 8 frame.`In orderto prevent ,the disc ,Sfronn` rotating I haveshovvnYanfapertured bar 10,

adaptedto fitoverprojeetingpins 1l on .the

01' slimline, le disc 7'` and;

hier y betyveen v`tlf'ie articles and theupper .shr-

y,than the 'discs In `order-to space thefcarrier frein the discsl'ha-veshown lipsor flanges 11i, turned down,adjacentl the 'apertures, andthesek flanges .serve to space the inain 'body Qfsaidcarrier away from-the ,lower disc' `to'better holdthe articles :tobe

lapped.A Y

Extending through one of `the, annular on. "ThisA crank 16 passes'through or `is otherwise secured to the carrier, preferably at thecenter of the latter. Aeap 17 Vinay be provided above `the crank, forypreventing beelrls- Y i When the Yapertures inthe carrier are arasive'niaterial frein enteringthe crank much larger than the 'size ofthe 4'articles .to

beV ,lamped,` spacer eleinents, such as discs 18,

may 'be provided to hold-the articles away from the center of theapertures. `Ths'ivill prevent" the "articles fron vreinaining in one:position relatively to. thel carrier. These spacer elei'nents arepreferablyvthinnervthan thefarticles being lappedzand, iffvery thin,

invaypbe spaced away frein one of the discs in any suitable-manner, asbyineans of fianges tothe flanges 14 on the carrier." In. order Ato"provide a `Ineans- ,for introducing an abrasive substancebetvvee'nthedises `and@ to4 lapped, I have indi- `catedfaire `uppersurfac'eof Ythel upper disc as `providedfvith[grooves A20, in 'which anabres i i be pour fro nuifture, such as leineryand oil, inay ed'. Aseriesfofapertures21-entends in theibotto'uis of thejgrooves and-through4dis in oiderf'toperhnit the .introduction lof'. tllieabrasiveibetiveenMt/he nlower surface of t he ,abrasive will passI dovvnand fa e4 of thezvlovverbdisc.'*The excess abrasive ,vvilflffallbetiveehV one of the discsfandfthe upstandinguflange 23,011 a part ofthe frane. The'. abiaslr 1rvsliflrg over" .the ,inner eds@ 0f 'in asingle aperture they from receiving more ineaiias of a pulleyBO. Thecarrier is what may rier will of course ment or a rmovementsubstantially radialV to will actually the annular discs will find itsway into the reservoir or container 24, and the abrasive mixture fromthese two containers may be received through pipes 25 and 26.

Due to'the relative size and positioning ofy the carrier aiidkdiscs andof the eccentricity of the crank shaft, some or all of the articlescarried by the carrier will at some time durf ing the lapping operationoverlap both the outside and inside edges of the annular discs, asindicated at 27, 2S. This slight overlapping of the discs by some or allof Vthe articles to-be lapped `insures `anieven and uniform wearingdownv of the lapping surfaces of said discs andprevents formation. of ashoulder or ridge thereon thus maintaining a true surface.

'The operation of the machine is as follows l The plates 7 and 8 areseparated and the articles to be lapped, for example, rings 19, areintroduced'into the carriers. rIhe spacer 18 if used is. placed Withintheapertures in the carrier to prevent the articles from moving abouttoo freely'or remaining at the center. lVhen a plurality of articles areplaced are preferably 'loosely arranged within the same to permit aninterchange or ticlesfrom a`position adjacent the spacer to a positionadjacent the edge of the aperture. This interchange Vwill prevent somearticles than others. ered onto the articles and an abrasivemixture,such as emery and'oil, is introduced between the discs and thesurfacesuof the ar# ticles. The shaft'l is next rotated, asby be termeda floating disc or carrie-r, for the latter is not eon strained to movein a predetermined definite path. The center is, of course, constrainedto move in a circle with the crank 16, butv other parts of the carriermay have very different and erratic motions. As a mattei' of facti ithas been foundin practice that, upon rotation of the crank, parts of thecarhave an oscillating movethe discs, without moving aroundthe center ofthe saine while at other times the carrier rotate relatively to thediscs in one directiongor the other. Ithas also been `found thatthearticles, when loosely disposed in the apertures will shift aroundtherein and will also tend to rotate about their own axes duiing theirmovement within thev apertures. The motions given to the articles beinglapped, while not absolutely definite and predetermined, will, ingeneral, be a movement in and out and around the discs relatively to thecenter thereof, and the individual articles will likewise turn andshiftcireumfrelitially within the apertures y eration,

the lapping d1scs,1both radially andy circuml specic shifting about ofthe ar-V of the abrasive action v The heavy plate is then llowo articlesaway from tures, said last mentioned iii the carrier.v lith themovementsas indicated, each article being lapped traverses, or may traverse inthe course of the lapping opsubstantiallyr the entire surface Aofferentially, and a highly accurate uand imifornr product is produced. y

While I have shown the discs as substantially horizontally mounted I donot necessarily wish to have it understood that all claims are limitedto; that arrangement. i Vhile I have shown and described the machine asa lapping machine, I wish it to be understood that either one or both ofthe lapping discs might be replacedr by discs having inherent abrasivequalities and that my ,invention is broad enough to include grinding aswellas lapping operations. y

` Although I have described in great detail embodiment of my invention,I wish it to and modifications` may be made therein within the scope ofthe appended claims.

A It will be noted thatthe so-called carrier 12.,functions as a mainspacer plate for the articles to be lapped, and that the so-called.discsf I8. function as secondary spacer plates for the articles to'belapped, and that all of said plates function conj ointly in spacing andcarrying the articles over the entire lapping surfaces of both lappingdiscs.

I claim: v

1.1In a lapping machine, a pair of discs having spaced lapping surfaces,a work carrier between said discs, and means for effecting a relativelyVoscillatory movement betveen said carrier and said discs, said cai'-i'icr being also rotatableabout its own center, and said work carrierhaving a pluralityof -apertures for loosely holding articles tobelappc'd, with means for separating a group of the articles beingoperated upon, said :separating: means being thinner than the ysaidarticles y 2Q In a lapping 'machine,a pair of discs having spacedlapping'surfaces, a work carrier 'between said discs, and means foreffecting ak relatively oscillatory movement between said carrier andsaid discs, said car'- rier being also rotatable about its own centei',and said work carrier having a plural ity of a-perturesfor looselyholding articles to belapped, with means 'for holding said the centersof said aper- V means being thinner than said articles.

3.A lapping machine including in combination, two opposed laps havingflat working surfaces, a work carriei' positioned between said .lapsandv having openings therein for'articles to be lapped, each' of saidvopenings being of a size'to hold a plurality and laps in asubstantially circular path, the

be understood that various changes bodily said means leaving the workcarrier tree to rotate about its own axis under the influence vot thearticles, the plurality of articles in each opening in the work carrierbeing free to rotate 'bodily about the axes of the openings so as toexecute a substantially planetary movement, and spacing means'thinnerthan said articles and operating to hold apart certain of said articles.Y

ll. A lapping machine including in combination, two opposed laps havingflat working surfaces, a work carrier positioned between said laps andhaving openings therein to contain a plurality of articles to be lapped,means for elifecting an eccentric motion between said work carrier andlaps, said means leaving the work carrier free to rotate about its ownaxis under the influence ot the articles, said openingsl `in the workcarrier being smaller than the elective ex tent oit' the laps by anamount slightly less4 than the total eccentricity ot' the movementbetween the work carrier and laps, whereby the articles in the openingsmay overlap the effective working surfaces of said laps and the articlesin said openings may rotate berlily about the aries ot said openings soas to execute a substantially planetary movement, and spacing meansthinner than said articles and operating te hold apart certain of saidarticles.

5. In a lapping machine, two annular laps having flat Working surfaces,a main work carrier positioned between said laps and movabletherebetween, said carrier having openings, at least one et said open`ings being oi suHicie-ut size to receive a plurality of devices to belapped, and means for spacing said devices in a ring-lille arrangementin said opening, driving means for imparting to the devices to be lappeda revolving motion around the center of the laps, a revolving motionaround the center of the carrier, and a revolving vmotion around thecenter of said opening, said spacing means ticles, a secondary plate tospace said ar-` ticles in such apertures in the main spacer plate, andmeans for producing relative movement between said plates and said discsY to effect the lapping oit said articles, said secondary plate beingthinner' than the articles being lapped.

7. ln a lapping machine, two co-acting lapping dises, a plate betweensaid discs having apertures for spacing articles to be lapped, certainof said apertures being large Aenough to receive a plurality of sucharticles, a secondary plate to space saidl articles in such apertures inthe main spacer plate, and means for producing relative movement betweensaid plates and discs to elliect thelapping ot said articles, saidsecondary plates spacing said articles incircular arrangement withinsaid apertures in the main spacer plate, and being thinner than thearticles being lapped.

JQHN lV. SMITH.

